package cn.bjc.filters;


import com.alibaba.fastjson.JSON;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

import java.io.UnsupportedEncodingException;
import java.util.HashMap;
import java.util.List;

@Component  //交给spring管理
public class LoginCheckFilter implements GlobalFilter, Ordered {

    // 创建日志器，可以使用slf4j提供的日志器进行日志打印
    private static final Logger log = LoggerFactory.getLogger(RequestTimeFilter.class);

    //执行此filter的业务方法
    //exchange:上下文对象
    //chain: filter调用链对象
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        //1.得到token
        ServerHttpRequest request = exchange.getRequest();
        String path = request.getURI().getPath();

        if (!path.endsWith("login") && !path.endsWith("register")) {
            List<String> token = request.getHeaders().get("token");
            log.info("用户的token信息为:{}", token);

            //2.判断token是否为空,如果为null,说明没有登陆,那么响应noLogin
            if (token == null || token.isEmpty()) {
                //设置响应对象
                ServerHttpResponse response = exchange.getResponse();
                //构建错误结果
                HashMap<String, Object> map = new HashMap<>();
                map.put("code", "401");
                map.put("success", false);
                map.put("message", "登录校验失败，请重新登录！");

                DataBuffer buffer = null;
                try {
                    //  4.转换参数，包装buffer对象
                    // 4.1.将数据转换为JSON，再转换为byte数组
                    byte[] bytes = JSON.toJSONString(map).getBytes("utf-8");
                    // 4.2.将byte数组包装到DataBuffer对象中，用于响应给浏览器，构建响应内容
                    buffer = response.bufferFactory().wrap(bytes);

                    // 5.设置完成响应，不会继续执行后面的filter
                    // 5.1.设置响应状态为401
                    response.setStatusCode(HttpStatus.UNAUTHORIZED);
                    // 5.2.设置响应格式
                    response.getHeaders().add("Content-Type", "application/json;charset=UTF-8");
                } catch (UnsupportedEncodingException e) {
                    e.printStackTrace();
                }

                // 6.把结果写给客户端
                return response.writeWith(Mono.just(buffer));
            }
            
        }

        log.info("token不为空,放行");
        // 7.token不为空，继续执行后续filter
        return chain.filter(exchange);
    }

    @Override
    public int getOrder() {
        return 0;
    }
}
